The present invention relates to pressurized-gas canister assemblies, and more specifically to metal hydride canister assemblies.
Canisters containing pressurized-gas are well-known in the art. Enclosures sealing such canisters are also well known in the art. Canister enclosures are frequently designed to permit a canister to be easily filled, emptied, and refilled. Pressurized-gas canisters frequently are hollow, cylindrical shells made in accordance with, for example, U.S. Department of Transportation (DOT) specifications, such as DOT 3AL. At one or both ends of the cylinder, enclosures seal the canister to maintain internal pressure and facilitate transfer of gas into and out of the canister. Depending on the function of the canister, the enclosure may include a resealable valve through which the canister is filled, emptied, and refilled. Typically a regulator or control valve attaches to, or is part of, the resealable valve on the canister.
Metal hydride canisters differ from typical high-pressure gas canisters in that the metal hydride disassociates within the canister into hydrogen gas and the metal ion, and the metal ion remains in the canister after the hydrogen gas is removed. The metal ion may be re-hydridized as a way to recharge the canister for future use. In comparison to gaseous hydrogen and liquid hydrogen storage, the advantages of metal hydride storage of hydrogen include the high volumetric density of hydrogen in the metal hydride, the ability to operate and store the metal hydride canisters at ambient temperature and pressure, and improved safety features.
The present invention is directed to pressurized-gas canister assemblies and to docking assemblies of pressurized-gas canister assemblies with manifold assemblies. A docking assembly may include a pressurized-gas canister assembly, a manifold assembly, a docking station, and a docking mechanism. A pressurized-gas canister assembly includes, for example, a canister, a plug enclosure, a heat transfer/decrepitation device, and a protective handle. The canister may be a light-weight, metal container having a narrow opening suitable for enclosure. The plug enclosure may be a hard, durable attachment appropriately sized to provide a tight seal with the opening of the canister capable of withstanding the internal pressure of the canister once pressurized. The plug enclosure may include a vent mechanism, for example, a pressure relief valve, a rupture disk, a fusible plug, or a combination of similar such devices. The plug enclosure also may include a delivery valve mechanism through which pressurized-gas is removed or added to the canister without unintentionally depressurizing the canister. The delivery valve mechanism permits the controlled delivery of gas into or out of canister, whereas the vent mechanism vents gas when the internal pressure of the canister exceeds a prescribed pressure.
The heat transfer/decrepitation device may reside inside the canister, conducting heat inward from the exterior shell of the canister towards the center of the canister. In addition, it also resists compaction and promotes decrepitation of the hydride alloy. The protective handle may envelop the plug enclosure and attach to the canister assembly for convenience. The protective handle provides a means for carrying the canister assembly, protects the plug enclosure, and facilitates the interconnection of the delivery valve mechanism of the plug enclosure with the valve interface of a manifold.
In an embodiment of the present invention, the pressurized gas canisters include metal hydride/hydrogen storage containers for use in, for example, hydrogen fuel cell generators. The products within this family will vary depending on their intended use, fuel storage capability and potential power output capability. In an exemplary embodiment of the present invention, the pressurized-gas canisters are intended to store metal hydride and supply hydrogen to a fuel cell module, wherein one metal hydride canister will produce 1 kW of A.C. electric power for a one hour period of time from a hydrogen-driven fuel cell module.
In another exemplary embodiment, the canister/manifold docking assembly could operate within a seamless, uninterrupted power source such as a fuel cell generator. For example, when such a generator is plugged into the grid supplied power, A.C. power would be supplied from the grid through the internal control system of the unit to the load. The on-board power source could be maintained in a standby mode until power is lost from the grid. The on-board control system could sense the loss of grid power and switch the load to backup power within, for example, xc2xd cycle of the 60 Hz waveform. A microprocessor-based control system would supervise the entire operation of the unit and communicate with the microprocessor in the D.C. fuel cell module to maintain proper operation of the unit. The fuel cell module could include all the necessary components (e.g., fuel cell stacks, air compressor, gas sensors, pressure regulators, etc.) to generate electricity from hydrogen. The initial energy to supply power to the load and controls could be derived from on-board batteries. When the load is switched to the standby power source, the control electronics also would activate the fuel cell D.C. power module. When the fuel cell module has completed its start-up sequence and is ready to supply power, it could share the energy burden with the batteries and also supply additional energy to recharge the batteries. Once the fuel cell module is supplying electrical energy, battery energy would only be required for surge loads in excess of the rated 1 kW capability of the unit. These surge loads would be those that might be expected when starting an electric motor.